The final lining is a fundamental stage. The final lining is the most important stage in the construction of a tunnel. It represent the final reinforcement which determines the durability and structural strength of the underground works, as well as being the support for the service installations such as final ventilation, aeration and lighting.
A number of technical considerations. There are a series of technical solutions for this stage, with special attention paid to an increase in the final quality, durability, safety and also appearance from an architectural point of view.
Maccaferri solutions can increase productivity while reducing lining thickness. For traditionally excavated tunnels, our Wirand® steel fibres are used to structurally reinforce the concrete final lining, which is poured or pumped directly into formwork. As traditional steel reinforcement can be reduced or even eliminated, productivity is increased and lining thickness may be reduced. Steel fibre reinforced concrete (SFRC) is more ductile, tougher and less permeable than traditional concrete. FibroMac® polymer fibres significantly increase fire resistance by reducing spalling phenomena. Finally, ceramic linings can provide an aesthetic finish to the tunnel.
Wirand® steel fibres can replace the traditional steel reinforcement method. Within TBM tunnels, the segmental precast concrete lining is also often the final lining. Whether this is for a large metro tunnel, or a small diameter service tunnel, our Wirand® steel fibres are used to structurally reinforce the segments, in some instances enabling the complete removal of all traditional steel reinforcement.
Maccaferri polymer fibres protect from fire damage. Fibromac™ polymer fibres are added to segments in order to dramatically increase the concrete’s resistance to high temperatures. This reduces explosive spalling and damage to tunnel linings exposed to fire.
Constantly striving for perfection. Using renowned testing and research establishments, we have repeatedly refined tunnel segment designs through the use of Wirand® SFRC, in doing so, saving clients’ money on projects.